Chris Hadfield, the Canadian astronaut who captivated the world with his Twitter updates from space, has announced his retirement.

"It has been an incredible adventure," Hadfield, 53, said of his 35 years of service as a Cold War fighter pilot and astronaut with the Canadian Space Agency.

Describing his recent mission to the International Space Station as "a kind of pinnacle of my entire career ... since I was a little dreaming kid of nine years old thinking of flying in space," he said it was "time now for me to do something else."

Astronaut Chris Hadfield as he announces his plans to retire from the Canadian Space Agency (AP)

"In about a month I'll be retiring from the Canadian Space Agency and just pursuing private interests," Hadfield told a press conference, "and getting my feet planted on the soil and seeing where the future takes me."

Cmdr Hadfield returned to Earth last month with American astronaut Tom Marshburn and Russian cosmonaut Roman Romanenko.

From space, Hadfield captured the public imagination with regular updates on Twitter that gave an unprecedented insight into daily life in space and access to spectacular images taken from the ISS.

Tweeting under the Star Trek-like name @Cmdr-Hadfield, the astronaut posted spectacular pictures of the Earth seen from the sky and also insights on the mundane aspects of things like eating and washing in space.

Using the power of social networks more effectively than anyone in the history of manned space flight, Hadfield has arguably become the world's most prominent astronaut since the days of Neil Armstrong and Buzz Aldrin.